This invention relates to a method and apparatus for rupturing a sliver during coiler can replacement, while the sliver producing apparatus, such as a carding machine, a roller card unit or a drafting unit continues to supply the sliver. The sliver trumpet and calender rolls are rotatably supported.
In a known apparatus, such as disclosed in German Pat. No. 1,091,010, prior to or during the coiler can replacement the distance between the sliver trumpet arranged on the upper portion of the rotary head of the sliver coiler and the downstream arranged calender rollers is increased for a short period of time to such an extent that the sliver breaks between the trumpet and the calender rollers. At the ruptured sliver end, close to the trumpet outlet, a fuzzy fiber beard is formed which prevents the calender rollers from securely grasping the new leading end of the sliver. Further, it is a disadvantage of such a prior art arrangement that while the trumpet dwells in its upwardly swung position, the carding machine continues to supply sliver, but the calender rollers do not withdraw the sliver from the trumpet. This may cause significant operational disturbances. It is a further disadvantage that the provision of a pivotal plate and a driven plunger constitute an excessively complex construction.
German Offenlegungsschrift (application published without examination) No. 1,510,428 discloses an apparatus wherein during the can replacement the distance between the sliver feeding device and the uppermost sliver coil in the can may be lengthened for a short period of time to an extent as to cause rupture of the sliver. In this known apparatus the rotating sliver channel in the rotary coiler head is, prior to the removal of the full can, immobilized in a position in which the outlet of the sliver channel is oriented in a direction opposite to that in which the coiler can is removed. This known arrangement has the disadvantage that because of immobilizing the sliver channel, a continuous supply of the sliver during coiler can replacement does not take place. Since the differential speed between the stationary sliver channel and the outwardly moving coiler is insufficient for securely rupturing the sliver, the sliver channel is arranged obliquely with respect to the longitudinal axis of the coiler can in order to ensure a sharp deflection of the sliver at the outlet of the sliver channel.